Rebuilding a data slice of a maintenance free storage container

ABSTRACT

A method begins by a dispersed storage (DS) processing module detecting a storage error of an encoded data slice associated with a storage server within a maintenance free storage container. The method continues with the DS processing module determining failure mode information for the storage server and other storage servers and determining a rebuilding protocol for the encoded data. When the determined rebuilding protocol is a zero information gain (ZIG) protocol, the method continues with the DS processing module identifying a decode threshold number of storage servers from the other storage servers of the maintenance free storage container and from storage servers of another maintenance free storage container, retrieving zero information gain (ZIG) partial encoded data slices from the decode threshold number of storage servers, and decoding the ZIG partial encoded data slices utilizing a ZIG dispersed storage error coding function to reproduce the encoded data slice.

CROSS REFERENCE TO RELATED PATENTS

The present U.S. Utility Patent Application claims priority pursuant to35 U.S.C. §119(e) to U.S. Provisional Application No. 61/505,010,entitled “Optimizing a Container Based Dispersed Storage Network,” filedJul. 6, 2011, which is incorporated herein by reference in its entiretyand made part of the present U.S. Utility Patent Application for allpurposes.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

NOT APPLICABLE

INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC

NOT APPLICABLE

BACKGROUND OF THE INVENTION

1. Technical Field of the Invention

This invention relates generally to computing systems and moreparticularly to data storage solutions within such computing systems.

2. Description of Related Art

Computers are known to communicate, process, and store data. Suchcomputers range from wireless smart phones to data centers that supportmillions of web searches, stock trades, or on-line purchases every day.In general, a computing system generates data and/or manipulates datafrom one form into another. For instance, an image sensor of thecomputing system generates raw picture data and, using an imagecompression program (e.g., JPEG, MPEG, etc.), the computing systemmanipulates the raw picture data into a standardized compressed image.

With continued advances in processing speed and communication speed,computers are capable of processing real time multimedia data forapplications ranging from simple voice communications to streaming highdefinition video. As such, general-purpose information appliances arereplacing purpose-built communications devices (e.g., a telephone). Forexample, smart phones can support telephony communications but they arealso capable of text messaging and accessing the internet to performfunctions including email, web browsing, remote applications access, andmedia communications (e.g., telephony voice, image transfer, musicfiles, video files, real time video streaming. etc.).

Each type of computer is constructed and operates in accordance with oneor more communication, processing, and storage standards. As a result ofstandardization and with advances in technology, more and moreinformation content is being converted into digital formats. Forexample, more digital cameras are now being sold than film cameras, thusproducing more digital pictures. As another example, web-basedprogramming is becoming an alternative to over the air televisionbroadcasts and/or cable broadcasts. As further examples, papers, books,video entertainment, home video, etc., are now being stored digitally,which increases the demand on the storage function of computers.

A typical computer storage system includes one or more memory devicesaligned with the needs of the various operational aspects of thecomputer's processing and communication functions. Generally, theimmediacy of access dictates what type of memory device is used. Forexample, random access memory (RAM) memory can be accessed in any randomorder with a constant response time, thus it is typically used for cachememory and main memory. By contrast, memory device technologies thatrequire physical movement such as magnetic disks, tapes, and opticaldiscs, have a variable response time as the physical movement can takelonger than the data transfer, thus they are typically used forsecondary memory (e.g., hard drive, backup memory, etc.).

A computer's storage system will be compliant with one or more computerstorage standards that include, but are not limited to, network filesystem (NFS), flash file system (FFS), disk file system (DFS), smallcomputer system interface (SCSI), internet small computer systeminterface (iSCSI), file transfer protocol (FTP), and web-baseddistributed authoring and versioning (WebDAV). These standards specifythe data storage format (e.g., files, data objects, data blocks,directories, etc.) and interfacing between the computer's processingfunction and its storage system, which is a primary function of thecomputer's memory controller.

Despite the standardization of the computer and its storage system,memory devices fail; especially commercial grade memory devices thatutilize technologies incorporating physical movement (e.g., a discdrive). For example, it is fairly common for a disc drive to routinelysuffer from bit level corruption and to completely fail after threeyears of use. One solution is to utilize a higher-grade disc drive,which adds significant cost to a computer.

Another solution is to utilize multiple levels of redundant disc drivesto replicate the data into two or more copies. One such redundant driveapproach is called redundant array of independent discs (RAID). In aRAID device, a RAID controller adds parity data to the original databefore storing it across the array. The parity data is calculated fromthe original data such that the failure of a disc will not result in theloss of the original data. For example, RAID 5 uses three discs toprotect data from the failure of a single disc. The parity data, andassociated redundancy overhead data, reduces the storage capacity ofthree independent discs by one third (e.g., n−1=capacity). RAID 6 canrecover from a loss of two discs and requires a minimum of four discswith a storage capacity of n−2.

While RAID addresses the memory device failure issue, it is not withoutits own failure issues that affect its effectiveness, efficiency andsecurity. For instance, as more discs are added to the array, theprobability of a disc failure increases, which increases the demand formaintenance. For example, when a disc fails, it needs to be manuallyreplaced before another disc fails and the data stored in the RAIDdevice is lost. To reduce the risk of data loss, data on a RAID deviceis typically copied on to one or more other RAID devices. While thisaddresses the loss of data issue, it raises a security issue sincemultiple copies of data are available, which increases the chances ofunauthorized access. Further, as the amount of data being stored grows,the overhead of RAID devices becomes a non-trivial efficiency issue.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

FIG. 1 is a schematic block diagram of an embodiment of a computingsystem in accordance with the present invention;

FIG. 2 is a schematic block diagram of an embodiment of a computing corein accordance with the present invention;

FIG. 3 is a schematic block diagram of an embodiment of a distributedstorage processing unit in accordance with the present invention;

FIG. 4 is a schematic block diagram of an embodiment of a grid module inaccordance with the present invention;

FIG. 5 is a diagram of an example embodiment of error coded data slicecreation in accordance with the present invention;

FIG. 6 is a schematic block diagram of another embodiment of a computingsystem in accordance with the present invention;

FIG. 7 is a flowchart illustrating an example of migrating slices inaccordance with the present invention;

FIG. 8 is a flowchart illustrating another example of migrating slicesin accordance with the present invention;

FIG. 9 is a schematic block diagram of another embodiment of a computingsystem in accordance with the present invention;

FIG. 10 is a flow chart illustrating an example of modifyingconnectivity in accordance with the present invention;

FIG. 11A is a schematic block diagram of another embodiment of acomputing system in accordance with the present invention;

FIG. 11B is a flowchart illustrating an example of invoking securitymeasures in accordance with the present invention;

FIG. 12A is a schematic block diagram of another embodiment of acomputing system in accordance with the present invention;

FIG. 12B is a flowchart illustrating an example of rebuilding an encodeddata slice in accordance with the present invention;

FIG. 13A is a diagram illustrating an example of a storage containermemory structure in accordance with the present invention;

FIG. 13B is a diagram illustrating another example of a storagecontainer memory structure in accordance with the present invention;

FIG. 13C is a diagram illustrating another example of a storagecontainer memory structure in accordance with the present invention;

FIG. 14 is a diagram illustrating an example of a storage containermemory system in accordance with the present invention;

FIG. 15A is a diagram illustrating another example of a storagecontainer memory structure in accordance with the present invention;

FIG. 15B is a diagram illustrating another example of a storagecontainer memory structure in accordance with the present invention;

FIG. 15C is a diagram illustrating another example of a storagecontainer memory structure in accordance with the present invention;

FIG. 16 is a diagram illustrating another example of a storage containermemory system in accordance with the present invention;

FIG. 17A is a diagram illustrating another example of a storagecontainer memory structure in accordance with the present invention;

FIG. 17B is a diagram illustrating another example of a storagecontainer memory structure in accordance with the present invention;

FIG. 17C is a diagram illustrating another example of a storagecontainer memory structure in accordance with the present invention;

FIG. 18 is a diagram illustrating another example of a storage containermemory system in accordance with the present invention;

FIG. 19A is a schematic block diagram of an embodiment of a maintenancefree storage container in accordance with the present invention; and

FIG. 19B is a flowchart illustrating an example of accessing a storagemodule of a maintenance free storage container.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a schematic block diagram of a computing system 10 thatincludes one or more of a first type of user devices 12, one or more ofa second type of user devices 14, at least one distributed storage (DS)processing unit 16, at least one DS managing unit 18, at least onestorage integrity processing unit 20, and a distributed storage network(DSN) memory 22 coupled via a network 24. The network 24 may include oneor more wireless and/or wire lined communication systems; one or moreprivate intranet systems and/or public internet systems; and/or one ormore local area networks (LAN) and/or wide area networks (WAN).

The DSN memory 22 includes a plurality of distributed storage (DS) units36 for storing data of the system. Each of the DS units 36 includes aprocessing module and memory and may be located at a geographicallydifferent site than the other DS units (e.g., one in Chicago, one inMilwaukee, etc.).

Each of the user devices 12-14, the DS processing unit 16, the DSmanaging unit 18, and the storage integrity processing unit 20 may be aportable computing device (e.g., a social networking device, a gamingdevice, a cell phone, a smart phone, a personal digital assistant, adigital music player, a digital video player, a laptop computer, ahandheld computer, a video game controller, and/or any other portabledevice that includes a computing core) and/or a fixed computing device(e.g., a personal computer, a computer server, a cable set-top box, asatellite receiver, a television set, a printer, a fax machine, homeentertainment equipment, a video game console, and/or any type of homeor office computing equipment). Such a portable or fixed computingdevice includes a computing core 26 and one or more interfaces 30, 32,and/or 33. An embodiment of the computing core 26 will be described withreference to FIG. 2.

With respect to the interfaces, each of the interfaces 30, 32, and 33includes software and/or hardware to support one or more communicationlinks via the network 24 indirectly and/or directly. For example,interfaces 30 support a communication link (wired, wireless, direct, viaa LAN, via the network 24, etc.) between the first type of user device14 and the DS processing unit 16. As another example, DSN interface 32supports a plurality of communication links via the network 24 betweenthe DSN memory 22 and the DS processing unit 16, the first type of userdevice 12, and/or the storage integrity processing unit 20. As yetanother example, interface 33 supports a communication link between theDS managing unit 18 and any one of the other devices and/or units 12,14, 16, 20, and/or 22 via the network 24.

In general and with respect to data storage, the system 10 supportsthree primary functions: distributed network data storage management,distributed data storage and retrieval, and data storage integrityverification. In accordance with these three primary functions, data canbe distributedly stored in a plurality of physically different locationsand subsequently retrieved in a reliable and secure manner regardless offailures of individual storage devices, failures of network equipment,the duration of storage, the amount of data being stored, attempts athacking the data, etc.

The DS managing unit 18 performs distributed network data storagemanagement functions, which include establishing distributed datastorage parameters, performing network operations, performing networkadministration, and/or performing network maintenance. The DS managingunit 18 establishes the distributed data storage parameters (e.g.,allocation of virtual DSN memory space, distributed storage parameters,security parameters, billing information, user profile information,etc.) for one or more of the user devices 12-14 (e.g., established forindividual devices, established for a user group of devices, establishedfor public access by the user devices, etc.). For example, the DSmanaging unit 18 coordinates the creation of a vault (e.g., a virtualmemory block) within the DSN memory 22 for a user device (for a group ofdevices, or for public access). The DS managing unit 18 also determinesthe distributed data storage parameters for the vault. In particular,the DS managing unit 18 determines a number of slices (e.g., the numberthat a data segment of a data file and/or data block is partitioned intofor distributed storage) and a read threshold value (e.g., the minimumnumber of slices required to reconstruct the data segment).

As another example, the DS managing module 18 creates and stores,locally or within the DSN memory 22, user profile information. The userprofile information includes one or more of authentication information,permissions, and/or the security parameters. The security parameters mayinclude one or more of encryption/decryption scheme, one or moreencryption keys, key generation scheme, and data encoding/decodingscheme.

As yet another example, the DS managing unit 18 creates billinginformation for a particular user, user group, vault access, publicvault access, etc. For instance, the DS managing unit 18 tracks thenumber of times user accesses a private vault and/or public vaults,which can be used to generate a per-access bill. In another instance,the DS managing unit 18 tracks the amount of data stored and/orretrieved by a user device and/or a user group, which can be used togenerate a per-data-amount bill.

The DS managing unit 18 also performs network operations, networkadministration, and/or network maintenance. As at least part ofperforming the network operations and/or administration, the DS managingunit 18 monitors performance of the devices and/or units of the system10 for potential failures, determines the devices and/or unit'sactivation status, determines the devices' and/or units' loading, andany other system level operation that affects the performance level ofthe system 10. For example, the DS managing unit 18 receives andaggregates network management alarms, alerts, errors, statusinformation, performance information, and messages from the devices12-14 and/or the units 16, 20, 22. For example, the DS managing unit 18receives a simple network management protocol (SNMP) message regardingthe status of the DS processing unit 16.

The DS managing unit 18 performs the network maintenance by identifyingequipment within the system 10 that needs replacing, upgrading,repairing, and/or expanding. For example, the DS managing unit 18determines that the DSN memory 22 needs more DS units 36 or that one ormore of the DS units 36 needs updating.

The second primary function (i.e., distributed data storage andretrieval) begins and ends with a user device 12-14. For instance, if asecond type of user device 14 has a data file 38 and/or data block 40 tostore in the DSN memory 22, it sends the data file 38 and/or data block40 to the DS processing unit 16 via its interface 30. As will bedescribed in greater detail with reference to FIG. 2, the interface 30functions to mimic a conventional operating system (OS) file systeminterface (e.g., network file system (NFS), flash file system (FFS),disk file system (DFS), file transfer protocol (FTP), web-baseddistributed authoring and versioning (WebDAV), etc.) and/or a blockmemory interface (e.g., small computer system interface (SCSI), internetsmall computer system interface (iSCSI), etc.). In addition, theinterface 30 may attach a user identification code (ID) to the data file38 and/or data block 40.

The DS processing unit 16 receives the data file 38 and/or data block 40via its interface 30 and performs a distributed storage (DS) process 34thereon (e.g., an error coding dispersal storage function). The DSprocessing 34 begins by partitioning the data file 38 and/or data block40 into one or more data segments, which is represented as Y datasegments. For example, the DS processing 34 may partition the data file38 and/or data block 40 into a fixed byte size segment (e.g., 2¹ to2^(n) bytes, where n=>2) or a variable byte size (e.g., change byte sizefrom segment to segment, or from groups of segments to groups ofsegments, etc.).

For each of the Y data segments, the DS processing 34 error encodes(e.g., forward error correction (FEC), information dispersal algorithm,or error correction coding) and slices (or slices then error encodes)the data segment into a plurality of error coded (EC) data slices 42-48,which is represented as X slices per data segment. The number of slices(X) per segment, which corresponds to a number of pillars n, is set inaccordance with the distributed data storage parameters and the errorcoding scheme. For example, if a Reed-Solomon (or other FEC scheme) isused in an n/k system, then a data segment is divided into n slices,where k number of slices is needed to reconstruct the original data(i.e., k is the threshold). As a few specific examples, the n/k factormay be 5/3; 6/4; 8/6; 8/5; 16/10.

For each EC slice 42-48, the DS processing unit 16 creates a uniqueslice name and appends it to the corresponding slice EC 42-48. The slicename includes universal DSN memory addressing routing information (e.g.,virtual memory addresses in the DSN memory 22) and user-specificinformation (e.g., user ID, file name, data block identifier, etc.).

The DS processing unit 16 transmits the plurality of EC slices 42-48 toa plurality of DS units 36 of the DSN memory 22 via the DSN interface 32and the network 24. The DSN interface 32 formats each of the slices fortransmission via the network 24. For example, the DSN interface 32 mayutilize an internet protocol (e.g., TCP/IP, etc.) to packetize the ECslices 42-48 for transmission via the network 24.

The number of DS units 36 receiving the EC slices 42-48 is dependent onthe distributed data storage parameters established by the DS managingunit 18. For example, the DS managing unit 18 may indicate that eachslice is to be stored in a different DS unit 36. As another example, theDS managing unit 18 may indicate that like slice numbers of differentdata segments are to be stored in the same DS unit 36. For example, thefirst slice of each of the data segments is to be stored in a first DSunit 36, the second slice of each of the data segments is to be storedin a second DS unit 36, etc. In this manner, the data is encoded anddistributedly stored at physically diverse locations to improve datastorage integrity and security.

Each DS unit 36 that receives an EC slice 42-48 for storage translatesthe virtual DSN memory address of the slice into a local physicaladdress for storage. Accordingly, each DS unit 36 maintains a virtual tophysical memory mapping to assist in the storage and retrieval of data.

The first type of user device 12 performs a similar function to storedata in the DSN memory 22 with the exception that it includes the DSprocessing. As such, the device 12 encodes and slices the data fileand/or data block it has to store. The device then transmits the slices11 to the DSN memory via its DSN interface 32 and the network 24.

For a second type of user device 14 to retrieve a data file or datablock from memory, it issues a read command via its interface 30 to theDS processing unit 16. The DS processing unit 16 performs the DSprocessing 34 to identify the DS units 36 storing the slices of the datafile and/or data block based on the read command. The DS processing unit16 may also communicate with the DS managing unit 18 to verify that theuser device 14 is authorized to access the requested data.

Assuming that the user device is authorized to access the requesteddata, the DS processing unit 16 issues slice read commands to at least athreshold number of the DS units 36 storing the requested data (e.g., toat least 10 DS units for a 16/10 error coding scheme). Each of the DSunits 36 receiving the slice read command, verifies the command,accesses its virtual to physical memory mapping, retrieves the requestedslice, or slices, and transmits it to the DS processing unit 16.

Once the DS processing unit 16 has received a read threshold number ofslices for a data segment, it performs an error decoding function andde-slicing to reconstruct the data segment. When Y number of datasegments has been reconstructed, the DS processing unit 16 provides thedata file 38 and/or data block 40 to the user device 14. Note that thefirst type of user device 12 performs a similar process to retrieve adata file and/or data block.

The storage integrity processing unit 20 performs the third primaryfunction of data storage integrity verification. In general, the storageintegrity processing unit 20 periodically retrieves slices 45, and/orslice names, of a data file or data block of a user device to verifythat one or more slices have not been corrupted or lost (e.g., the DSunit failed). The retrieval process mimics the read process previouslydescribed.

If the storage integrity processing unit 20 determines that one or moreslices is corrupted or lost, it rebuilds the corrupted or lost slice(s)in accordance with the error coding scheme. The storage integrityprocessing unit 20 stores the rebuild slice, or slices, in theappropriate DS unit(s) 36 in a manner that mimics the write processpreviously described.

FIG. 2 is a schematic block diagram of an embodiment of a computing core26 that includes a processing module 50, a memory controller 52, mainmemory 54, a video graphics processing unit 55, an input/output (10)controller 56, a peripheral component interconnect (PCI) interface 58,an IO interface 60, at least one 10 device interface module 62, a readonly memory (ROM) basic input output system (BIOS) 64, and one or morememory interface modules. The memory interface module(s) includes one ormore of a universal serial bus (USB) interface module 66, a host busadapter (HBA) interface module 68, a network interface module 70, aflash interface module 72, a hard drive interface module 74, and a DSNinterface module 76. Note the DSN interface module 76 and/or the networkinterface module 70 may function as the interface 30 of the user device14 of FIG. 1. Further note that the 10 device interface module 62 and/orthe memory interface modules may be collectively or individuallyreferred to as 10 ports.

FIG. 3 is a schematic block diagram of an embodiment of a dispersedstorage (DS) processing module 34 of user device 12 and/or of the DSprocessing unit 16. The DS processing module 34 includes a gatewaymodule 78, an access module 80, a grid module 82, and a storage module84. The DS processing module 34 may also include an interface 30 and theDSnet interface 32 or the interfaces 68 and/or 70 may be part of userdevice 12 or of the DS processing unit 16. The DS processing module 34may further include a bypass/feedback path between the storage module 84to the gateway module 78. Note that the modules 78-84 of the DSprocessing module 34 may be in a single unit or distributed acrossmultiple units.

In an example of storing data, the gateway module 78 receives anincoming data object that includes a user ID field 86, an object namefield 88, and the data object field 40 and may also receivecorresponding information that includes a process identifier (e.g., aninternal process/application ID), metadata, a file system directory, ablock number, a transaction message, a user device identity (ID), a dataobject identifier, a source name, and/or user information. The gatewaymodule 78 authenticates the user associated with the data object byverifying the user ID 86 with the managing unit 18 and/or anotherauthenticating unit.

When the user is authenticated, the gateway module 78 obtains userinformation from the management unit 18, the user device, and/or theother authenticating unit. The user information includes a vaultidentifier, operational parameters, and user attributes (e.g., userdata, billing information, etc.). A vault identifier identifies a vault,which is a virtual memory space that maps to a set of DS storage units36. For example, vault 1 (i.e., user 1's DSN memory space) includeseight DS storage units (X=8 wide) and vault 2 (i.e., user 2's DSN memoryspace) includes sixteen DS storage units (X=16 wide). The operationalparameters may include an error coding algorithm, the width n (number ofpillars X or slices per segment for this vault), a read threshold T, awrite threshold, an encryption algorithm, a slicing parameter, acompression algorithm, an integrity check method, caching settings,parallelism settings, and/or other parameters that may be used to accessthe DSN memory layer.

The gateway module 78 uses the user information to assign a source name35 to the data. For instance, the gateway module 78 determines thesource name 35 of the data object 40 based on the vault identifier andthe data object. For example, the source name may contain a fileidentifier (ID), a vault generation number, a reserved field, and avault identifier (ID). As another example, the gateway module 78 maygenerate the file ID based on a hash function of the data object 40.Note that the gateway module 78 may also perform message conversion,protocol conversion, electrical conversion, optical conversion, accesscontrol, user identification, user information retrieval, trafficmonitoring, statistics generation, configuration, management, and/orsource name determination.

The access module 80 receives the data object 40 and creates a series ofdata segments 1 through Y 90-92 in accordance with a data storageprotocol (e.g., file storage system, a block storage system, and/or anaggregated block storage system). The number of segments Y may be chosenor randomly assigned based on a selected segment size and the size ofthe data object. For example, if the number of segments is chosen to bea fixed number, then the size of the segments varies as a function ofthe size of the data object. For instance, if the data object is animage file of 4,194,304 eight bit bytes (e.g., 33,554,432 bits) and thenumber of segments Y=131,072, then each segment is 256 bits or 32 bytes.As another example, if segment sized is fixed, then the number ofsegments Y varies based on the size of data object. For instance, if thedata object is an image file of 4,194,304 bytes and the fixed size ofeach segment is 4,096 bytes, the then number of segments Y=1,024. Notethat each segment is associated with the same source name.

The grid module 82 receives the data segments and may manipulate (e.g.,compression, encryption, cyclic redundancy check (CRC), etc.) each ofthe data segments before performing an error coding function of theerror coding dispersal storage function to produce a pre-manipulateddata segment. After manipulating a data segment, if applicable, the gridmodule 82 error encodes (e.g., Reed-Solomon, Convolution encoding,Trellis encoding, etc.) the data segment or manipulated data segmentinto X error coded data slices 42-44.

The value X, or the number of pillars (e.g., X=16), is chosen as aparameter of the error coding dispersal storage function. Otherparameters of the error coding dispersal function include a readthreshold T, a write threshold W, etc. The read threshold (e.g., T=10,when X=16) corresponds to the minimum number of error-free error codeddata slices required to reconstruct the data segment. In other words,the DS processing module 34 can compensate for X-T (e.g., 16−10=6)missing error coded data slices per data segment. The write threshold Wcorresponds to a minimum number of DS storage units that acknowledgeproper storage of their respective data slices before the DS processingmodule indicates proper storage of the encoded data segment. Note thatthe write threshold is greater than or equal to the read threshold for agiven number of pillars (X).

For each data slice of a data segment, the grid module 82 generates aunique slice name 37 and attaches it thereto. The slice name 37 includesa universal routing information field and a vault specific field and maybe 48 bytes (e.g., 24 bytes for each of the universal routinginformation field and the vault specific field). As illustrated, theuniversal routing information field includes a slice index, a vault ID,a vault generation, and a reserved field. The slice index is based onthe pillar number and the vault ID and, as such, is unique for eachpillar (e.g., slices of the same pillar for the same vault for anysegment will share the same slice index). The vault specific fieldincludes a data name, which includes a file ID and a segment number(e.g., a sequential numbering of data segments 1-Y of a simple dataobject or a data block number).

Prior to outputting the error coded data slices of a data segment, thegrid module may perform post-slice manipulation on the slices. Ifenabled, the manipulation includes slice level compression, encryption,CRC, addressing, tagging, and/or other manipulation to improve theeffectiveness of the computing system.

When the error coded data slices of a data segment are ready to beoutputted, the grid module 82 determines which of the DS storage units36 will store the EC data slices based on a dispersed storage memorymapping associated with the user's vault and/or DS storage unitattributes. The DS storage unit attributes may include availability,self-selection, performance history, link speed, link latency,ownership, available DSN memory, domain, cost, a prioritization scheme,a centralized selection message from another source, a lookup table,data ownership, and/or any other factor to optimize the operation of thecomputing system. Note that the number of DS storage units 36 is equalto or greater than the number of pillars (e.g., X) so that no more thanone error coded data slice of the same data segment is stored on thesame DS storage unit 36. Further note that EC data slices of the samepillar number but of different segments (e.g., EC data slice 1 of datasegment 1 and EC data slice 1 of data segment 2) may be stored on thesame or different DS storage units 36.

The storage module 84 performs an integrity check on the outboundencoded data slices and, when successful, identifies a plurality of DSstorage units based on information provided by the grid module 82. Thestorage module 84 then outputs the encoded data slices 1 through X ofeach segment 1 through Y to the DS storage units 36. Each of the DSstorage units 36 stores its EC data slice(s) and maintains a localvirtual DSN address to physical location table to convert the virtualDSN address of the EC data slice(s) into physical storage addresses.

In an example of a read operation, the user device 12 and/or 14 sends aread request to the DS processing unit 16, which authenticates therequest. When the request is authentic, the DS processing unit 16 sendsa read message to each of the DS storage units 36 storing slices of thedata object being read. The slices are received via the DSnet interface32 and processed by the storage module 84, which performs a parity checkand provides the slices to the grid module 82 when the parity check wassuccessful. The grid module 82 decodes the slices in accordance with theerror coding dispersal storage function to reconstruct the data segment.The access module 80 reconstructs the data object from the data segmentsand the gateway module 78 formats the data object for transmission tothe user device.

FIG. 4 is a schematic block diagram of an embodiment of a grid module 82that includes a control unit 73, a pre-slice manipulator 75, an encoder77, a slicer 79, a post-slice manipulator 81, a pre-slice de-manipulator83, a decoder 85, a de-slicer 87, and/or a post-slice de-manipulator 89.Note that the control unit 73 may be partially or completely external tothe grid module 82. For example, the control unit 73 may be part of thecomputing core at a remote location, part of a user device, part of theDS managing unit 18, or distributed amongst one or more DS storageunits.

In an example of write operation, the pre-slice manipulator 75 receivesa data segment 90-92 and a write instruction from an authorized userdevice. The pre-slice manipulator 75 determines if pre-manipulation ofthe data segment 90-92 is required and, if so, what type. The pre-slicemanipulator 75 may make the determination independently or based oninstructions from the control unit 73, where the determination is basedon a computing system-wide predetermination, a table lookup, vaultparameters associated with the user identification, the type of data,security requirements, available DSN memory, performance requirements,and/or other metadata.

Once a positive determination is made, the pre-slice manipulator 75manipulates the data segment 90-92 in accordance with the type ofmanipulation. For example, the type of manipulation may be compression(e.g., Lempel-Ziv-Welch, Huffman, Golomb, fractal, wavelet, etc.),signatures (e.g., Digital Signature Algorithm (DSA), Elliptic Curve DSA,Secure Hash Algorithm, etc.), watermarking, tagging, encryption (e.g.,Data Encryption Standard, Advanced Encryption Standard, etc.), addingmetadata (e.g., time/date stamping, user information, file type, etc.),cyclic redundancy check (e.g., CRC32), and/or other data manipulationsto produce the pre-manipulated data segment.

The encoder 77 encodes the pre-manipulated data segment 92 using aforward error correction (FEC) encoder (and/or other type of erasurecoding and/or error coding) to produce an encoded data segment 94. Theencoder 77 determines which forward error correction algorithm to usebased on a predetermination associated with the user's vault, a timebased algorithm, user direction, DS managing unit direction, controlunit direction, as a function of the data type, as a function of thedata segment 92 metadata, and/or any other factor to determine algorithmtype. The forward error correction algorithm may be Golay,Multidimensional parity, Reed-Solomon, Hamming, Bose Ray ChauduriHocquenghem (BCH), Cauchy-Reed-Solomon, or any other FEC encoder. Notethat the encoder 77 may use a different encoding algorithm for each datasegment 92, the same encoding algorithm for the data segments 92 of adata object, or a combination thereof.

The encoded data segment 94 is of greater size than the data segment 92by the overhead rate of the encoding algorithm by a factor of X/T, whereX is the width or number of slices, and T is the read threshold. In thisregard, the corresponding decoding process can accommodate at most X-Tmissing EC data slices and still recreate the data segment 92. Forexample, if X=16 and T=10, then the data segment 92 will be recoverableas long as 10 or more EC data slices per segment are not corrupted.

The slicer 79 transforms the encoded data segment 94 into EC data slicesin accordance with the slicing parameter from the vault for this userand/or data segment 92. For example, if the slicing parameter is X=16,then the slicer 79 slices each encoded data segment 94 into 16 encodedslices.

The post-slice manipulator 81 performs, if enabled, post-manipulation onthe encoded slices to produce the EC data slices. If enabled, thepost-slice manipulator 81 determines the type of post-manipulation,which may be based on a computing system-wide predetermination,parameters in the vault for this user, a table lookup, the useridentification, the type of data, security requirements, available DSNmemory, performance requirements, control unit directed, and/or othermetadata. Note that the type of post-slice manipulation may includeslice level compression, signatures, encryption, CRC, addressing,watermarking, tagging, adding metadata, and/or other manipulation toimprove the effectiveness of the computing system.

In an example of a read operation, the post-slice de-manipulator 89receives at least a read threshold number of EC data slices and performsthe inverse function of the post-slice manipulator 81 to produce aplurality of encoded slices. The de-slicer 87 de-slices the encodedslices to produce an encoded data segment 94. The decoder 85 performsthe inverse function of the encoder 77 to recapture the data segment90-92. The pre-slice de-manipulator 83 performs the inverse function ofthe pre-slice manipulator 75 to recapture the data segment 90-92.

FIG. 5 is a diagram of an example of slicing an encoded data segment 94by the slicer 79. In this example, the encoded data segment 94 includesthirty-two bits, but may include more or less bits. The slicer 79disperses the bits of the encoded data segment 94 across the EC dataslices in a pattern as shown. As such, each EC data slice does notinclude consecutive bits of the data segment 94 reducing the impact ofconsecutive bit failures on data recovery. For example, if EC data slice2 (which includes bits 1, 5, 9, 13, 17, 25, and 29) is unavailable(e.g., lost, inaccessible, or corrupted), the data segment can bereconstructed from the other EC data slices (e.g., 1, 3 and 4 for a readthreshold of 3 and a width of 4).

FIG. 6 is a schematic block diagram of another embodiment of a computingsystem. The system includes a user device 14, a dispersed storage (DS)processing unit 16, and a plurality of sites 100, 102. Each site of theplurality of sites 100, 102 may be located at different geographiclocations providing geographic diversity. The sites provide a physicalinstallation environment, required power, and network connectivity(e.g., wireline and/or wireless) to other sites of a dispersed storagenetwork (DSN). Each site of the plurality of sites hosts one or moremaintenance free containers of a plurality of containers 108-114 andeach site hosts at least one site controller of a plurality of sitecontrollers 104-106. For each site, the at least one site controller maybe implemented as a separate computing unit (e.g., a server) or as afunction within one or more of the one or more containers.

Each container (e.g., a shipping container, a box, a sealed environment,a tanker, a thermal control pool) of the one or more containers includesone or more of network connectivity, one or more DS units 1-U (e.g.,storage servers), at least one container controller of a plurality ofcontainer controllers 116-122, environmental control (e.g., heating andcooling), and a power input 124. The at least one container controllermay be implemented as a separate computing unit or as a function withinthe one or more DS units 1-U. For example, container 1 108 at site 1 100includes a container controller 1 116 and DS units 1-U associated withcontainer 1 108 and container 2 110 at site 1 100 includes a containercontroller 2 118 and DS units 1-U associated with container 2 110.

The at least one site controller assists in container operationsassociated with a common site. For example, site controller 1 104receives an access request from DS processing unit 16 and facilitatesaccess to the one or more containers 108-110 associated with sitecontroller 1 104. As another example, site controller 1 104 facilitatesmigration of stored encoded data slices 11 from container 1 108 of site1 100 to container 2 110 of site 1 100 based on migration criteria.

The at least one container controller assists in container operationsassociated with the at least one container controller. For example,container controller 2 122 of container 2 114 of site 2 102 receives anaccess request from DS processing unit 16 and facilitates access to theone or more DS units 1-U associated with the container controller 2 122.As another example, container controller 1 120 of container 1 112 ofsite 2 102 facilitates migration of stored encoded data slices 11 fromDS unit 2 of container 1 112 of site 2 102 to DS unit 10 of container 1112 of site 2 102 based on migration criteria.

In an example of storing data, encoded data slices 11 associated witheach pillar of a pillar width number of a set of encoded data slices arestored within a common container. For instance, the DS processing unit16 dispersed storage error encodes data to produce a plurality of setsof encoded data slices 11, wherein each set of the plurality of sets ofencoded data slices includes four pillars of encoded data slices when apillar width is four. Next, the DS processing unit 16 facilitate storageof each set of four encoded data slices of the plurality of sets ofencoded data slices 11 in DS units 1-4 of container 1 108 at site 1 100.In an example of retrieving the data, the DS processing unit 16facilitates retrieval of at least three encoded data slices 11 from DSunits 1-4 of container 1 108 at site 1 100 when a decode threshold isthree. In an example of rebuilding an encoded data slice of a set of theplurality of sets of encoded data slices, container controller 1 116 atsite 1 100 retrieves at least three encoded data slices 11 from DS units1-4 of container 1 108 at site 1 100 and dispersed storage error decodesthe at least three encoded data slices to reproduce a data segmentassociated with an encoded data slice to be rebuilt. Next, the containercontroller 1 116 at site 1 100 dispersed storage error encodes the datasegment to reproduce the data slice to be rebuilt.

In another example storing data, encoded data slices associated witheach pillar of the pillar with number of the set of encode slices arestored within two or more containers of a common site. For instance, aDS processing unit 16 facilitates storage of two encoded data slices ofeach set of four encoded data slices of the plurality of sets of encodeddata slices 11 in DS units 1-2 of container 1 112 at site 2 102 andfacilitates storage of a remaining two encoded data slices of each setof four encoded data slices of the plurality of sets of encoded dataslices in DS units 1-2 of container 2 114 at site 2 102.

In an example of retrieving the data, the DS processing unit 16facilitates retrieval of at least three encoded data slices 11 from DSunits 1-2 of container 1 112 at site 2 102 and DS units 1-2 of container2 114 at site 2 102. In an example of rebuilding an encoded data sliceof a set of the plurality of sets of encoded data slices 11, sitecontroller 2 106 at site 2 102 retrieves at least three encoded dataslices 11 from DS units 1-2 of container 1 112 at site 2 102 and DSunits 1-2 of container 2 114 at site 2 102 and dispersed storage errordecodes the at least three encoded data slices to reproduce a datasegment associated with an encoded data slice to be rebuilt. Next, thesite controller 2 106 at site 2 102 dispersed storage error encodes thedata segment to reproduce the data slice to be rebuilt.

FIG. 7 is a flowchart illustrating an example of migrating slices. Themethod begins at step 130 where a processing model (e.g., a sitecontroller) obtains site container status. The site container statusincludes a container status indicator for one more maintenance freestorage containers of a common site. The container status indicatorincludes one or more of a container loading indicator, a containerperformance indicator, and a container environmental indicator. Theobtaining may be based on one or more of a query, a test, sensor data, arecord lookup, and an error message.

The method continues at step 132 where the processing module determineswhether the site container status compares favorably to a statusthreshold. The status threshold includes one or more of a loadingthreshold, a performance threshold, and an environmental indicatorthreshold. The determining includes determining whether a containerstatus associated with each container of a common site comparesfavorably to the status threshold. For example, the processing moduledetermines that the site container status compares unfavorably to thestatus threshold when a container environmental indicator indicates thata container temperature is less than a low temperature environmentalindicator threshold. As another example, the processing moduledetermines that the site container status compares unfavorably to thestatus threshold when the container performance indicator is less thanthe performance threshold. As yet another example, the processing moduledetermines that the site container status compares unfavorably to thestatus threshold when the container loading indicator is greater thanthe loading threshold. The method loops back to step 130 when theprocessing module determines that the site container status comparesfavorably to the status threshold. The method continues to step 134 whenthe processing module determines that the site container status comparesunfavorably to the status threshold.

The method continues at step 134 where the processing module determinesslices to migrate from an unfavorable container associated with theunfavorable comparison. The determining includes identifying slice namesof a subset of a plurality of slices stored in dispersed storage (DS)units of the unfavorable container based on one or more of the sitecontainer status, a nature of the unfavorable comparison, and migrationtable. For example, the processing module determines to move all slicesof the plurality of slices when a nature of the unfavorable comparisonis a high temperature environmental indicator. As another example, theprocessing module determines to move half of the plurality of sliceswhen a nature of the unfavorable comparison is a high container loadingindicator.

The method continues at step 136 where the processing module determinesa receiving container. The determining includes selecting a containerthat includes DS units associated with a site container status thatcompares favorably to a receiving container threshold. For example, theprocessing module selects a site container that has favorable loadingcapacity when the nature of the unfavorable comparison is the highcontainer loading indicator.

The method continues at step 138 where the processing module facilitatesmigration of the slices to migrate from the unfavorable container to thereceiving container. The facilitating includes at least one of sending amigration request to a site controller associated with the unfavorablecontainer, wherein the request includes the slice names to migrate, andretrieving the slices to migrate and sending the slices to migrate toone of DS units of the receiving container and a site controller of thereceiving container.

The method continues at step 140 where the processing module updatesslice location information. The slice location information includes oneor more of a slice name, a corresponding container identifier, and acorresponding DS unit identifier. The updating includes at least one ofmodifying a local slice location information table and sending alocation table update request that includes one or more of the slicename, the corresponding container identifier, and the corresponding DSunit identifier.

FIG. 8 is a flowchart illustrating another example of migrating slices,which include similar steps to FIG. 7. The method begins at step 142where a processing model (e.g., a container controller) obtains localcontainer status. The local container status includes a dispersedstorage (DS) unit status indicator for one more DS units of a commoncontainer. The DS unit status indicator includes one or more of a DSunit loading indicator, a DS unit performance indicator, and a DS unitenvironmental indicator. The obtaining may be based on one or more of aquery, a test, sensor data, a record lookup, and an error message.

The method continues at step 144 where the processing module determineswhether the local container status compares favorably to a statusthreshold. The status threshold includes one or more of a loadingthreshold, a performance threshold, and an environmental indicatorthreshold. The determining includes determining whether a DS unit statusassociated with each DS unit of a common container compares favorably tothe status threshold. For example, the processing module determines thatthe local container status compares unfavorably to the status thresholdwhen a DS unit environmental indicator indicates that a cont DS unittemperature is greater than a high temperature environmental indicatorthreshold. As another example, the processing module determines that thelocal container status compares unfavorably to the status threshold whena DS unit performance indicator is less than the performance threshold.As yet another example, the processing module determines that the localcontainer status compares unfavorably to the status threshold when a DSunit available memory indicator is less than an available memorythreshold. The method loops back to step 142 when the processing moduledetermines that the local container status compares favorably to thestatus threshold. The method continues to step 146 when the processingmodule determines that the local container status compares unfavorablyto the status threshold.

The method continues at step 146 where the processing module determinesslices to migrate from an unfavorable DS unit associated with theunfavorable comparison. The determining identifies slice names of asubset of a plurality of slices stored in the DS unit based on one ormore of the local container status, a nature of the unfavorablecomparison, and migration table. For example, the processing moduledetermines to move all slices of the plurality of slices when a natureof the unfavorable comparison is a DS unit of high temperatureenvironmental indicator. As another example, the processing moduledetermines to move half of the plurality of slices when a nature of theunfavorable comparison is a high DS unit loading indicator.

The method continues at step 148 where the processing module determinesa receiving DS unit. The determining includes selecting a DS unitassociated with a local container status that compares favorably to areceiving local container threshold. For example, the processing moduleselects a DS unit that has favorable loading capacity when the nature ofthe unfavorable comparison is a high DS unit loading indicator.

The method continues at step 150 where the processing module facilitatesmigration of the slices to migrate from the unfavorable DS unit to thereceiving DS unit. The facilitation includes at least one of sending amigration request to the unfavorable DS unit, wherein the requestincludes the slice names to migrate, and retrieving the slices tomigrate from the unfavorable DS unit and sending the slices to migrateto one of the receiving DS unit and a container controller associatedwith the receiving DS unit. The method continues with step 140 of FIG. 7where the processing module updates slice location information such thatthe slices are associated with the receiving DS unit and not associatedwith the unfavorable DS unit.

FIG. 9 is a schematic block diagram of another embodiment of a computingsystem that includes a site 154, a network 24, a dispersed storage (DS)processing unit 16, and a user device 14. The site 154 includes awireless router 156, a site controller 158, and containers 160-162. Thewireless router 156 includes a slice memory 164. The slice memory mayinclude a temporary slice memory (e.g., for storing encoded data sliceson a temporary basis) and a non-temporary slice memory (e.g., forstoring encoded data slices on a non-temporary basis).

The wireless router 156 may operate in accordance with one or moreindustry standards (e.g., WIFI, Bluetooth, global system for mobilecommunications (GSM), code division multiple access (CDMA), etc.) totransmit and receive local area signals 166. The wireless router 156 isfurther operable to convert slices into local area signals 166 fortransmission to the containers 160-162 and to convert received localarea signals 166 from containers 160-162 into slices.

The containers 160-162 include a wireless transceiver 1-2, a containercontroller 1-2, and DS units 1-U. The wireless transceivers 1-2 convertsreceived local area signals 166 from the wireless router 156 into slicesand converts slices into local area signals 166 for transmission to thewireless router 156. The wireless transceivers 1-2 may operate inaccordance with one or more industry standards (e.g., WIFI, Bluetooth,global system for mobile communications (GSM), code division multipleaccess (CDMA), etc.) to receive and transmit local area signals 166.

The containers 160-162 may be operably coupled to the network 24 via atleast one of the local area signals 166 and a wireline connection 168.For example, container 160 couples to network 24 via the local areasignals 166 and container 162 couples to network 24 via the local areasignals 166 and the wireline connection 168. The site controller 158assigns the containers 160-162 to dispersed storage network (DSN)storage tasks based on available connectivity. For example, the sitecontroller 158 assigns container 162 to accommodate heavier storagetraffic when available connectivity includes a highest bandwidthwireline connection to container 162. As another example, the sitecontroller 158 assigns container 160 to accommodate low priority storagetraffic when the available connectivity includes a moderate bandwidthwireless connection to container 160. As yet another example, the sitecontroller 158 assigns container 160 to accommodate new storage trafficwhen the available connectivity includes sufficient bandwidth wirelessconnection to container 160 and container 160 includes more availablestorage capacity than container 162. For instance, container 160 isimplemented in site 154 by connecting temporary power and utilizingwireless connectivity rather than establishing wireline connectivity.

FIG. 10 is a flow chart illustrating an example of modifyingconnectivity. The method begins at step 170 where a processing module(e.g., a site controller) obtains site connectivity status. The siteconnectivity status includes one or more of a wireless connectivityavailability indicator, a wireline connectivity availability indicator,a wireless connectivity performance indicator, and a wirelineconnectivity performance indicator. The obtaining may be based on one ormore of a query, a test, sensor data, a record lookup, and an errormessage.

The method continues at step 172 where the processing module determineswhether to modify site connectivity configuration. The configurationincludes one or more of utilizing a wireline connection and utilizing awireless connection. The determining may be based on one or more of thesite connectivity status, a site connectivity status threshold, and acomparison of the site connectivity status to the site connectivitystatus threshold. For example, the processing module determines tomodify the site connectivity configuration when a wireless connectivityperformance indicator is less than a wireless connectivity statusthreshold. As another example, the processing module determines tomodify the site connectivity configuration when a wireline connectivityavailability indicator indicates that a wireline connection is no longeravailable. The method loops back to step 170 when the processing moduledetermines not to modify the site connectivity configuration. The methodcontinues to step 174 when the processing module determines to modifythe site connectivity configuration.

The method continues at step 174 where the processing module determinesa modified site connectivity configuration. The determining may be basedon one or more of identifying a connectivity issue, discoveringconnectivity alternatives, quantifying connectivity alternatives, andselecting a connectivity alternative. For example, the processing moduledetermines the modified site connectivity configuration such that anadditional connectivity path is utilized (e.g., adding wirelessconnectivity to wireline connectivity when the wireline connectivityalone did not satisfy a performance requirement). As another example,the processing module determines the modified site connectivityconfiguration such that an alternative connectivity path is utilized(e.g., utilizing wireline connectivity instead of wireless connectivitywhen the wireline connectivity is associated with greater bandwidth thanthe wireless connectivity and bandwidth was identified as a connectivityissue).

The method continues at step 176 where the processing module facilitatesimplementation of the modified site connectivity configuration. Thefacilitation includes one or more of updating routing tables, sending areconfiguration message to one or more elements within a site, sending areconfiguration message to an external element, and testing elements ofthe system associated with the new configuration.

FIG. 11A is a schematic block diagram of another embodiment of acomputing system that includes a computing device 180 and a maintenancefree storage container 182. The maintenance free storage container 182includes a plurality of storage servers 184. Each storage server 184 mayinclude at least one of a memory device, a plurality of memory devices,and a dispersed storage (DS) unit. The computing device 180 may beimplemented as at least one of a site controller, a containercontroller, a user device, a DS processing unit, a DS unit, a DSmanaging unit, and any other computing device operable to couple withthe maintenance free storage container 182. The computing device 180includes a DS module 186. The DS module 186 includes an identifysecurity threat module 188, determine failure mode module 190, and asecurity threat countermeasure module 192.

The identify security threat module 188 identifies a security threat 194for the maintenance free storage container 182, wherein the maintenancefree storage container 182 allows for multiple storage servers 184 of aplurality of storage servers 184 to be in a failure mode withoutreplacement. The security threat includes at least one of a physicalsecurity threat type (e.g., breech of the maintenance free storagecontainer 182) and a data access security threat type (e.g., improperaccess of data stored in the maintenance free storage container 182).The identifying may be based on one or more of an error message, anintrusion detection message, an alarm indicator, a cyber threatindicator, a wireless receiver signal, a temperature change profile, aradiological detector output, a biological detector output, and achemical output detector.

The determine failure mode module 190 determines a failure mode level196 that is indicative of whether one or more of the multiple storageservers 184 are in the failure mode. The determine failure mode module190 functions to determine the failure mode level 196 of the maintenancefree storage container 182 in a variety of ways. In a first way, thedetermine failure mode module 190 determines that one or more storagelocations within a first storage server 184 of the plurality of storageservers 184 has failed. In a second way, the determine failure modemodule 190 determines that a second storage server 184 of the pluralityof storage servers 184 has failed. In a third way, the determine failuremode module 190 determines that a third storage server 184 of theplurality of storage servers 184 is operating at less than a desiredstorage level but greater than a storage failure level. In a fourth way,the determine failure mode module 190 identifies one or more failureimpacted storage vaults associated with at least one of the firststorage server 184, the second storage server 184, and the third storageserver 184.

The security threat countermeasure module 192 selects a security threatcountermeasure 198 based on the security threat 194 and the failure modelevel 196 and implements the security threat countermeasure 198. Forexample, the security threat countermeasure module 192 selectsdeactivating access to high-priority encoded data slices when a type ofsecurity threat detected is an intrusion detection. As another example,the security threat countermeasure module 192 selects migrating slicesfrom storage servers 184 of the maintenance free storage container 182to storage servers of another maintenance free storage container whenthe security threat 194 includes a flash fire detection. As yet anotherexample, the security threat countermeasure module 192 selects deletingslices from storage servers 184 of the maintenance free storagecontainer 182 when the security threat includes an unauthorized opencontainer hatch.

The security threat countermeasure module 192 further functions toselect one or more security threat countermeasures to include deleting aselected number of encoded data slices for one or more sets of encodeddata slices of a plurality of sets of encoded data slices correspondingto a storage vault in accordance with the failure mode level 196 of themaintenance free storage container 182 and the one or more failureimpacted storage vaults. For example, the selected number of encodeddata slices includes a pillar width number minus a read thresholdnumber. The deleting may include identifying sensitive encoded dataslices (e.g., slices that are most undesirable for attack). The deletingmay further include identifying sensitive encryption keys associatedwith storage of encoded data slices in the maintenance free storagecontainer 182.

The identify security threat module 188 further functions to indicate aphysical security threat type when detecting a physical anomalycondition of the maintenance free storage container 182. The physicalanomaly condition includes a variety of conditions including at leastone of an unauthorized open access door alarm, a pressure change alarm,an ambient light change alarm, localized wireless energy alarm, anextreme temperature alarm, a smoke alarm, a radiological detector alarm,a biological detector alarm, an atmospheric detector alarm, and achemical detector alarm. The security threat countermeasure module 192further functions to select a physical security threat typecountermeasure. The selecting includes at least one of a countermeasurelist lookup based on the physical security threat type, performing atest to acquire further threat type information, receiving a user input,and estimating a level of favorability of impact of a countermeasure.

The physical security threat type countermeasure includes one or more ofa variety of countermeasures. A first countermeasure includes migratingat least some data stored in the plurality of storage servers to anothermaintenance free storage container. For example, the security threatcountermeasure module 192 migrates encoded data slices from theplurality of storage servers to another maintenance free storagecontainer such that less than a decode threshold number of encoded dataslices per data segment remain in the plurality of storage servers. Asecond countermeasure includes deleting one or more encryption keysutilized to access the data. A third countermeasure includes deleting atleast some of the data stored in the plurality of storage servers. Forexample, the security threat countermeasure module 192 deletes encodeddata slices that expose data. As another example, the security threatcountermeasure module 192 deletes encoded data slices from the pluralityof stored servers such that at least a decode threshold number ofencoded data slices per data segment remain in the plurality of storedservers. A fourth countermeasure includes deactivating one or morestorage servers of the plurality of storage servers.

The identify security threat module 188 module further functions toindicate a data access security threat type when detecting unauthorizedaccess of data from one or more storage servers 184 of the plurality ofstorage servers 184. The detecting includes at least one of receiving aslice access request from an unauthorized requester, detecting anunfavorable data access pattern, receiving a cyber threat indicator, anddetecting a monitoring device. The security threat countermeasure module192 further functions to select a data access security threat typecountermeasure. The selecting includes at least one of a countermeasurelist lookup based on the data access security threat type, performing atest to acquire further threat type information, receiving a user input,and estimating a level of favorability of impact of a countermeasure.

The data access security threat type countermeasure includes one or moreof a variety of countermeasures. A first countermeasure includesrandomly accessing the data to produce a pseudorandom electromagneticpattern. A second countermeasure includes outputting random data inresponse to a data request from a requesting entity associated with athreat pattern. A third countermeasure includes migrating at least somedata stored in the plurality of storage servers 184 to anothermaintenance free storage container. A fourth countermeasure includesdeleting one or more encryption keys utilized to access the data. Afifth countermeasure includes deleting at least some of the data storedin the plurality of storage servers 184. A sixth countermeasure includesdeactivating one or more storage servers 184 of the plurality of storageservers 184.

FIG. 11B is a flowchart illustrating an example of invoking securitymeasures. The method begins at step 200 where a processing module (e.g.,of a site controller, a container controller, a user device, a dispersedstorage (DS) processing unit, a DS unit, a DS managing unit) identifiesa security threat for a maintenance free storage container, wherein themaintenance free storage container allows for multiple storage serversof a plurality of storage servers to be in a failure mode withoutreplacement. The processing module indicates a physical security threattype when detecting a physical anomaly condition of the maintenance freestorage container. The processing module indicates a data accesssecurity threat type when detecting unauthorized access of data from oneor more storage servers of the plurality of storage servers.

The method continues at step 202 where the processing module determinesa failure mode level that is indicative of whether one or more of themultiple storage servers are in the failure mode. The determining thefailure mode level of the maintenance free storage container may beaccomplished in variety of ways. For example, the processing moduledetermines that one or more storage locations within a first storageserver of the plurality of storage servers has failed. As anotherexample, the processing module determines that a second storage serverof the plurality of storage servers has failed. As yet another example,the processing module determines that a third storage server of theplurality of storage servers is operating at less than a desired storagelevel but greater than a storage failure level. As a still furtherexample, the processing module identifies one or more failure impactedstorage vaults associated with at least one of the first storage server,the second storage server, and the third storage server.

The method continues at step 204 where the processing module selects asecurity threat countermeasure based on the security threat and thefailure mode level. The method continues at step 206 where theprocessing module implements the security threat countermeasure. Theselecting the one or more security threat countermeasures includesdeleting a selected number of encoded data slices for one or more setsof encoded data slices of a plurality of sets of encoded data slicescorresponding to a storage vault in accordance with the failure modelevel of the maintenance free storage container and the one or morefailure impacted storage vaults. The processing module selects aphysical security threat type countermeasure when detecting a physicalanomaly condition of the maintenance free storage container. Theprocessing module selects a data access security threat typecountermeasure when detecting unauthorized access of data from one ormore storage servers of the plurality of storage servers.

The physical security threat type countermeasure includes a variety ofcountermeasures. For example, the processing module migrates at leastsome data stored in the plurality of storage servers to anothermaintenance free storage container. As another example, the processingmodule deletes one or more encryption keys utilized to access the data.As yet another example, the processing module deletes at least some ofthe data stored in the plurality of storage servers. As a still furtherexample, the processing module deactivates one or more storage serversof the plurality of storage servers.

The data access security threat type countermeasure includes a varietyof countermeasures. For example, the processing module randomly accessesthe data to produce a pseudorandom electromagnetic pattern. As anotherexample, the processing module outputs random data in response to a datarequest from a requesting entity associated with a threat pattern. Asyet another example, the processing module migrates at least some datastored in the plurality of storage servers to another maintenance freestorage container. As a still further example, the processing moduledeletes one or more encryption keys utilized to access the data and/orat least some of the data stored in the plurality of storage servers. Asyet a still further example, the processing module deactivates one ormore storage servers of the plurality of storage servers.

FIG. 12A is a schematic block diagram of another embodiment of acomputing system that includes a computing device 210 and at least twomaintenance free storage containers 212-214. Each maintenance freestorage container includes a plurality of storage servers 216. Eachstorage server 216 may include at least one of a memory device, aplurality of memory devices, and a dispersed storage (DS) unit. Thecomputing device 210 may be implemented as at least one of a sitecontroller, a container controller, a user device, a DS processing unit,a DS unit, a DS managing unit, and any other computing device operableto couple with the maintenance free storage containers 212-214. Thecomputing device 210 includes a DS module 218. The DS module 218includes a detect storage module 220, a determine failure modeinformation module 222, a determine rebuilding the protocol module 224,and a rebuild sliced module 226.

The maintenance free storage containers 212-214 allow for multiplestorage servers 216 of the plurality of storage servers 216 to be in afailure mode without replacement. Data is encoded using a dispersedstorage error coding function to produce a set of encoded data slices,which includes an encoded data slice 236. At least some encoded dataslices of the set of encoded data slices are stored in other storageservers 216 of the plurality of storage servers 216. The computingdevice 210 is operable to rebuild the encoded data slice 236 formaintenance free storage container 212. The detect storage error module220 detects a storage error 228 of the encoded data slice 236 associatedwith a storage server 216 of a plurality of storage servers 216 withinmaintenance free storage container 212.

The detect storage error module 220 functions to detect the storageerror 228 of the encoded data slice 236 in a variety of ways. In a firstway, the detect storage module 220 indicates the storage error 228 whena list response from the storage server compares unfavorably to at leastanother list response from the other storage servers. As such, the listresponse exposes one or more of a missing slice and a missing slicerevision. The detecting includes issuing a list and/or list digestrequest and receiving a list and/or list digest response. In a secondway, the detect storage module 220 indicates the storage error 228 whena calculated slice integrity value compares unfavorably to a retrievedslice integrity value corresponding to the encoded data slice (e.g.,hash mismatch). In a third way, the detect storage module 220 indicatesthe storage error 228 when determining that the storage server is in thefailure mode (e.g., storage error when the storage server has failed).In a fourth way, the detect storage module 220 receives a storage errormessage. In a fifth way, the detect storage module 220 receives arebuilding request, wherein the rebuilding request includes a slice nameassociated with the encoded data slice.

The determine failure mode information module 222 determines failuremode information 230 for the storage server 216 and the other storageservers 216. The determine failure mode information module 222 functionsto determine the failure mode information 230 by at least one ofdetermining that one or more storage locations within a first storageserver 216 of the storage server 216 and of the other storage servers216 has failed, determining that a second storage server 216 of thestorage server 216 and of the other storage servers 216 has failed, anddetermining that a third storage server 216 of the storage server 216and of the other storage servers 216 is operating at less than a desiredstorage level but greater than a storage failure level.

The determine rebuilding protocol module 224 determines a rebuildingprotocol 232 for the encoded data slice 236 based on the failure modeinformation 230 and whether at least a decode threshold of the otherstorage servers 216 are available. The determine rebuilding protocolmodule 224 functions to determine the rebuilding protocol 232 bydetermining whether quantity of the other storage servers 216 is atleast equal to a decode threshold number and when the quantity of theother storage servers 216 is less than the decode threshold number,identifying the ZIG protocol as the rebuilding protocol 232.

The rebuild slice module 226, when the determined rebuilding protocol isa zero information gain (ZIG) protocol, identifies a decode thresholdnumber of storage servers 216 from the other storage servers 216 of themaintenance free storage container 212 and from storage servers 216 ofanother maintenance free storage container 214 (e.g., at least some ofthe set of encoded data slices were previously stored at anothermaintenance free storage container). Next, the rebuild sliced module 226retrieves zero information gain (ZIG) partial encoded data slices 238from the decode threshold number of storage servers 216 and decodes theZIG partial encoded data slices 238 utilizing a ZIG dispersed storageerror coding function to reproduce the encoded data slice 236.

The rebuild slice module 226 functions to retrieve the decode thresholdnumber of zero information gain (ZIG) partial encoded data slices 238corresponding to the encoded data slice 236 by generating a decodethreshold number of ZIG partial encoded data slice requests based onidentity of the encoded data slice 236 and pillar numbers associatedwith the decode threshold number of storage servers 216. The ZIG partialencoded data slice request may include one or more of a slice name ofthe encoded data slice 236 to be rebuilt, a pillar number associatedwith the encoded data slice 236, pillar numbers associated withparticipant storage servers 216, an encoding matrix of the dispersedstorage error coding function, and an inverted square matrixcorresponding to ZIG rebuilding of the encoded data slice 236. Next, therebuild slice module 226 outputs the decode threshold number of ZIGpartial encoded data slice requests to the decode threshold number ofstorage servers 216. Next, the rebuild slice module 226 receives thedecode threshold number of ZIG partial encoded data slices 238 from thedecode threshold number of storage servers 216. The rebuild slice module226 functions to decode the decode threshold number of ZIG partialencoded data slices 238 by exclusive ORing the decode threshold numberof ZIG partial encoded data slices 238 to reproduce the encoded dataslice 236.

A storage server 216 of the decode threshold number of storage servers216 is operable to generate a ZIG partial encoded data slice 238 byobtaining an encoding matrix utilized to generate the encoded data slice236 (e.g., extracted from the ZIG partial encoded data slice request,retrieved from a memory), reducing the encoding matrix to produce asquare matrix that exclusively includes rows identified in the partialrebuilding request (e.g., pillars associated with participating storageservers 216 of the decode threshold number of storage servers 216),inverting the square matrix to produce an inverted matrix (e.g.alternatively, may extract the inverted matrix from the ZIG partialencoded data slice request), matrix multiplying the inverted matrix by acorresponding encoded data slice retrieved from memory of the storageserver 216 to produce a vector, and matrix multiplying the vector by arow of the encoding matrix corresponding to the encoded data slice 236to be rebuilt (e.g. alternatively, may extract the row from the ZIGpartial encoded data slice request), to produce the ZIG partial encodeddata slice 238.

The rebuild slice module 226, when the determined rebuilding protocol232 is a data-based rebuild protocol (e.g., when the quantity of theother storage servers 216 is at least the decode threshold number),retrieves a decode threshold number of encoded data slices 234 of theset of encoded data slices from the other storage servers 216 anddecodes the decode threshold number of encoded data slices 234 utilizingthe dispersed storage error coding function to reproduce the data. Next,the rebuild slice module 226 encodes the data utilizing the dispersedstorage error coding function to reproduce the encoded data slice 236.

FIG. 12B is a flowchart illustrating an example of rebuilding an encodeddata slice. The method begins at step 240 where a processing module(e.g., of a site controller, a container controller, a user device, adispersed storage (DS) processing unit, a DS unit, a DS managing unit)detects a storage error of an encoded data slice associated with astorage server of a plurality of storage servers within a maintenancefree storage container. The maintenance free storage container allowsfor multiple storage servers of the plurality of storage servers to bein a failure mode without replacement. Data is encoded using a dispersedstorage error coding function to produce a set of encoded data slices,which includes the encoded data slice, and wherein at least some encodeddata slices of the set of encoded data slices are stored in otherstorage servers of the plurality of storage servers.

The detecting the storage error of the encoded data slice includes atleast one of a variety of ways to detect the storage error. The varietyof ways to detect the storage error includes indicating the storageerror when a list response from the storage server compares unfavorablyto at least another list response from the other storage servers,indicating the slice error when a calculated slice integrity valuecompares unfavorably to a retrieved slice integrity value correspondingto the encoded data slice, indicating the slice error when determiningthat the storage server is in the failure mode, receiving a slice errormessage, and receiving a rebuilding request, wherein the rebuildingrequest includes a slice name associated with the encoded data slice.

The method continues at step 242 where the processing module determinesfailure mode information for the storage server and the other storageservers. The determining the failure mode information may beaccomplished in a variety of ways. In a first way, the processing moduledetermines that one or more storage locations within a first storageserver of the storage server and of the other storage servers hasfailed. In a second way, the processing module determines that a secondstorage server of the storage server and of the other storage servershas failed. In a third way, the processing module determines that athird storage server of the storage server and of the other storageservers is operating at less than a desired storage level but greaterthan a storage failure level.

The method continues at step 244 where the processing module determinesa rebuilding protocol for the encoded data slice based on the failuremode information and whether at least a decode threshold of the otherstorage servers are available. The rebuilding protocol includes at leastone of a data-based rebuild protocol (e.g., involving retrieving encodeddata slices associated with the encoded data slice of the storage error)and a zero information gain (ZIG) protocol (e.g., involving obtainingZIG partial encoded data slices associated with the encoded data sliceof the storage error). The determining the rebuilding protocol includesdetermining whether quantity of the other storage servers is at leastequal to a decode threshold number and when the quantity of the otherstorage servers is less than the decode threshold number, identifyingthe ZIG protocol.

When the determined rebuilding protocol is a data-based rebuildprotocol, the method continues at step 246 where the processing moduleretrieves a decode threshold number of encoded data slices of the set ofencoded data slices from the other storage servers. The retrievingincludes generating a decode threshold number of encoded data slicerequests and sending the decode threshold number of encoded data slicerequests to the other storage servers. The method continues at step 248where the processing module decodes the decode threshold number ofencoded data slices utilizing the dispersed storage error codingfunction to reproduce the data. The method continues at step 250 wherethe processing module encodes the data utilizing the dispersed storageerror coding function to reproduce the encoded data slice. In addition,the processing module may store the reproduce the encoded data slice inthe storage server.

When the determined rebuilding protocol is the ZIG protocol, the methodcontinues at step 252 where the processing module identifies a decodethreshold number of storage servers from the other storage servers ofthe maintenance free storage container and from storage servers ofanother maintenance free storage container. The method continues at step254 where the processing module retrieves ZIG partial encoded dataslices from the decode threshold number of storage servers. Theretrieving the decode threshold number of ZIG partial encoded dataslices corresponding to the encoded data slice includes generating adecode threshold number of ZIG partial encoded data slice requests basedon identity of the encoded data slice and pillar numbers associated withthe decode threshold number of storage servers. Next, the processingmodule outputs the decode threshold number of ZIG partial encoded dataslice requests to the decode threshold number of storage servers. Next,the processing module receives the decode threshold number of ZIGpartial encoded data slices from the decode threshold number of storageservers.

The method continues at step 256 where the processing module decodes theZIG partial encoded data slices utilizing a ZIG dispersed storage errorcoding function to reproduce the encoded data slice. The decoding thedecode threshold number of ZIG partial encoded data slices includesexclusive ORing the decode threshold number of ZIG partial encoded dataslices to reproduce the encoded data slice.

FIG. 13A is a diagram illustrating an example of a storage containermemory structure from a side view 262. The structure includes a thermotransfer structure 260 and a plurality of memory devices 1 _(—1), 2_(—1), through R_(—1) associated with a column of a matrix of memorydevices. Each memory device of the plurality of memory devices mayinclude one or more of a computing core, a power interface, acommunication interface and a memory. The memory may be implementedutilizing at least one of a solid-state memory, a magnetic disk drive,and an optical disk drive. The thermo transfer structure 260 providesstructural support to mounting the plurality of memory devices, provideswicking of heat from the plurality of memory devices, and may beimplemented utilizing at least one of a metal and a composite material.

Each memory device of the plurality of memory devices is mounted to thethermo transfer structure 260 such that heat generated by the memorydevice may be conducted to the thermo transfer structure 260. One ormore memory devices of the plurality of memory devices may be associatedwith a dispersed storage (DS) unit of a dispersed storage network (DSN)memory.

FIG. 13B is a diagram illustrating another example of a storagecontainer memory structure from a front view 264. The structure includesa thermo transfer structure 260 and a plurality of memory devicesorganized in a matrix of memory devices that includes C columns and Rrows. The matrix of memory devices may include hundreds or eventhousands of memory devices. As such, a significant amount of heat maybe generated by the plurality of memory devices and transferred to thethermo transfer structure 260.

FIG. 13C is a diagram illustrating another example of a storagecontainer memory structure from a top view 266. The structure includes athermal transfer structure 260 and a plurality of memory devices 1_(—1), 1 _(—2), through 1_C associated with a row of a matrix of memorydevices.

FIG. 14 is a diagram illustrating an example of a storage containermemory system that includes a containment system 268, piping 274, a pump270, and a heat exchanger 272. The containment system 268 contains amaintenance free storage container memory structure within a pool ofthermo transfer fluid 276. The maintenance free storage container memorystructure includes a thermo transfer structure 260 and a plurality ofmemory devices including memory devices 1 _(—1), 2 _(—1), throughR_(—1), associated with a column of memory devices, wherein theplurality of memory devices are affixed to the thermo transfer structure260. The thermo transfer fluid includes a heat transfer in material suchas at least one of a fluid (e.g., water), a slurry, a gas, and a solid.

The thermo transfer structure 260 absorbs heat from the plurality ofmemory devices and transfers at least some of the heat 278 to the thermotransfer fluid 276. The pump 270 pulls at least some of the thermotransfer fluid 276 as hot fluid 280 from the containment system 268 intothe piping 274. The pump 270 moves the hot fluid 280 to the heatexchanger 272 where at least some of the heat is emitted as excess heat282. The hot fluid 280 exits the heat exchanger 272 into the piping 274as cool fluid 284 and is pushed back into the containment system 268 bythe pump 270. The cycle continuously repeats to maintain a favorableaverage temperature of the thermo transfer fluid 276 within thecontainment system 268 providing thermal stability for the plurality ofmemory devices.

The pump 270 may be activated when a temperature of the thermo transferfluid 276 is above a high temperature threshold and deactivated when thetemperature of the thermal transfer fluid 276 is below a low temperaturethreshold. Alternatively, the pump may be activated when a storageactivity level of the plurality of memory devices is above a highstorage activity threshold and deactivated when the storage activitylevel of the plurality of memory devices is below a low storage activitythreshold.

FIG. 15A is a diagram illustrating another example of a storagecontainer memory structure from a side view 288. The structure includesan electrode a, an electrode b, and a plurality of memory devices 1_1,2_1, through R_1 associated with a column of a matrix of memory devices.One or more memory devices of the plurality of memory devices may beassociated with a dispersed storage (DS) unit of a dispersed storagenetwork (DSN) memory. Each memory device of the plurality of memorydevices may include one or more of a computing core, one or more powerconnections 290-292, a communication interface, and a memory, whereinthe memory may be implemented utilizing at least one of a solid-statememory, a magnetic disk drive, and an optical disk drive. Each powerconnection of the one or more power connections 290-292 includes atleast one of a power connector and a pass-through opening for a powerwire. For example, power is provided to a memory device via a powerconnection 290 associated with electrode a and another power connection292 associated with electrode b. The electrodes a-b provides structuralsupport to mount the plurality of memory devices, provides power to theplurality of memory devices via the power connections 290-292, createsstored battery power by interacting with an electrolyte when receivingexternal power, and may be implemented utilizing at least one of a metalassociated with batteries (e.g., lead).

FIG. 15B is a diagram illustrating another example of a storagecontainer memory structure from a front view 294. The structure includesan electrode a, and electrode b, and a plurality of memory devicesorganized in a matrix of memory devices that includes C columns and Rrows. The matrix of memory devices may include hundreds or eventhousands of memory devices. As such, a significant amount of power maybe required by the plurality of memory devices.

FIG. 15C is a diagram illustrating another example of a storagecontainer memory structure from a top view 296. The structure includesan electrode a, and electrode b, and a plurality of memory devices 1_1,1_2, through 1_C associated with a row of a matrix of memory devices.Each memory device of the plurality of memory devices includes a powerconnection 290 to electrode a and a second power connection 292 toelectrode b to receive operational power.

FIG. 16 is a diagram illustrating another example of a storage containermemory system that includes a containment system 300, a power source302, and power wires 304 coupling the power source 302 to thecontainment system 300. The containment system 300 contains a storagecontainer memory structure and an electrolyte 306 and may be implementedutilizing a suitable material such as at least one of metal, glass, anda composite material. The storage container memory structure includes atleast a plurality of memory devices 1_1, 2_1, through R_1, associatedwith a column of memory devices, affixed between an electrode a and anelectrode b. The electrolyte 306 includes a chemical agent (e.g., acid)to form a battery cell in conjunction with electrodes a-b. In addition,the electrolyte 306 may wick at least some excess heat from theplurality of memory devices by at least one of directly from theplurality of memory devices and via the electrodes a-b. Multiple storagecontainer memory structures may be implemented within the containmentsystem forming a serial connection of multiple battery cells.

The power source 302 provides power via the power wires to electrodesa-b. A charging power portion of the power interacts with electrodes a-band the electrolyte 306 to charge the battery cell. A memory devicepower portion of the power supplies operational power to the pluralityof memory devices. The electrodes a-b and the electrolyte interact toform a discharging battery cell when no power is provided by the powersource 302 and the battery cell is charged. The battery cell providesoperational power to the plurality of memory devices when the batterycell is discharging. The amount of power provided by the power sourcemay be raised when the battery cell is discharged and a storage activitylevel of the plurality of memory devices is above a high activitythreshold. The amount of power provided by the power source 302 may belowered when the battery cell is charged and storage activity level ofthe plurality of memory devices is below a low activity threshold. Thepower source 302 may be temporarily turned off to allow the battery cellto discharge powering the plurality of memory devices when activatingthe power source is unfavorable. For example, activating the powersource may be unfavorable based on a midday high cost of purchasingexternal power, a reliability level of external power, and/or a poorquality of external power.

FIG. 17A is a diagram illustrating another example of a storagecontainer memory structure from a side view 308. The structure includesa waveguide structure 310 and a plurality of memory devices 1_1, 2_1,through R_1 associated with a column of a matrix of memory devices. Oneor more memory devices of the plurality of memory devices may beassociated with a dispersed storage (DS) unit of a dispersed storagenetwork (DSN) memory. Each memory device of the plurality of memorydevices may include one or more of a computing core, a power interface,a wireless communication interface, and a memory, wherein the memory maybe implemented utilizing at least one of a solid-state memory, amagnetic disk drive, and an optical disk drive. The waveguide structure300 and provides one or more of structural support to mount theplurality of memory devices, wicking of heat from the plurality ofmemory devices, a wireless communication path, and may be implemented toform one or more waveguide channels 312 (e.g., free space tunnels withinthe waveguide structure) utilizing at least one of a metal and acomposite material. The waveguide channel 312 provides an enclosed pathfor wireless communications between two or more elements of thewaveguide structure 310 utilizing contained wireless signals.

FIG. 17B is a diagram illustrating another example of a storagecontainer memory structure from a front view 314. The structure includesa waveguide structure 310, a plurality of wireless routers 1-R, and aplurality of memory devices organized in a matrix of memory devices thatincludes C columns and R rows. The waveguide structure 300 and includesa plurality of waveguide channels 312 to provide enclosed wirelesscommunication paths between two or more elements mounted to thewaveguide structure 310. The matrix of memory devices may includehundreds or even thousands of memory devices. As such, a significantamount of element to element communication may be required by theplurality of memory devices. At least one wireless router of theplurality of wireless routers 1-R is associated with each waveguidechannel of the plurality of waveguide channels 312. Each wireless routerprovides communication between a controller 316 and a subset of memorydevices of the plurality of memory devices. For example, wireless router1 provides communication between the controller 316 and a subset ofmemory devices 1_1, 1_2, through 1_C associated with a first row of thematrix of memory devices.

Each memory device of the plurality of memory devices is mounted to thewaveguide structure 310 such that an antenna of a wireless transceiverassociated with the memory device is in close proximity to acorresponding waveguide channel 312 of the waveguide structure 310. Forexample, a horizontal waveguide channel 312 connects a subset of memorydevices and a wireless router associated with a common row. The wirelessrouter communicates contained wireless signal to each memory device of asubset of memory devices of the common row but not to other memorydevices of the plurality of memory devices. As another example, avertical waveguide channel 312 connects a plurality of memory devicesassociated with a common column to another wireless router, but not toother memory devices of the plurality of memory devices.

FIG. 17C is a diagram illustrating another example of a storagecontainer memory structure from a top view 318. The structure includes awaveguide structure 310, a wireless router 1, and a plurality of memorydevices 1_1, 1_2, through 1_C associated with a common row of a matrixof memory devices. Each memory device of the plurality of memory devicescommunicates with the wireless router 1 through a waveguide channel 312of the waveguide structure 310 via contained wireless signals.

FIG. 18 is a diagram illustrating another example of a storage containermemory system that includes a plurality of memory devices 1_1, 1_2,through 1_C, a waveguide channel 312, and a wireless router 1. Thewireless router includes a transceiver 322 and a router 326 andfunctions to convert data from a controller 316 into contained wirelesssignals 320 and converts contained wireless signals 320 into data tosend to the controller 316.

The waveguide channel 312 provides an enclosed wireless communicationspace such that the contained wireless signals 320 propagate freelybetween elements associated with the waveguide channel 312 but not withother elements not associated with the waveguide channel 312. Forexample, the contained wireless signals 320 may operate at a frequencyof 60 GHz and may be implemented in accordance with one or more industrystandards associated with 60 GHz. Each memory device of the plurality ofmemory devices includes a transceiver 322 and a memory 324. Thetransceiver 322 functions to convert received contained wireless signals320 into data for storage in the memory 324 and converts data retrievedfrom the memory 324 into contained wireless signals 320 for transmissionto the wireless router 1.

Each transceiver 322 of the plurality of memory devices and the wirelessrouter 1 is associated with an antenna 321, wherein the antenna 321functions to transmit and receive the contained wireless signals 320within the waveguide channel 312. In a first implementation, the antenna321 is just outside of the waveguide channel 312 within each transceiver322. In a second implication, the antenna 321 protrudes into thewaveguide channel 312 from each transceiver 322.

FIG. 19A is a schematic block diagram of an embodiment of a maintenancefree storage container 330 that includes a container control module 331and a plurality of storage modules 1_1, 1_2, through 1_C. Themaintenance-free storage container allows for multiple storage modulesof a plurality of storage modules to be in a failure mode withoutreplacement. The container control module 331 includes a dispersedstorage network (DSN) interface 32, a processing module 332, a slicelocation memory 336, and a transceiver 334. The plurality of storagemodules includes a sufficient number of storage modules to provide atleast one peta-byte of storage. Each storage module of the plurality ofstorage modules includes a transceiver 338, a control module 340 (e.g.,a hardware controller), one or more storage medium interfaces 342 andone or more storage mediums 343. Each storage medium 343 may beimplemented utilizing at least one of magnetic disk drive technology,tape technology, and optical disk drive technology.

The processing module 332 of the container control module 331 isoperable to determine failure mode information for the plurality ofstorage modules and manage storage mapping information 350 of datacontent within the plurality of storage modules based on the failuremode information. The slice location memory 336 is operable to store thestorage mapping information 350. The slice mapping information 350includes one or more entries by slice name, wherein each entry includesa slice name of a slice name field 352, a storage module identifier (ID)of a storage module ID field 354, and access request information of anaccess request information field 356 (e.g., position information). Forexample, an entry indicates that an encoded data slice associated withslice name A436 is stored at storage module 1_2, drive 1, at sector 5.The slice location memory 336 may be implemented as one or more of alocal memory associated with the container control module 331 one ormore of the storage modules 1_1 through 1_C.

The container control module 331 may be associated with a dispersedstorage (DS) unit or a DSN. When the container control module 331 isassociated with a DS unit, the container control module 331 manages thestorage mapping information of encoded data slices having common pillarreferences within their respective slices names within the plurality ofstorage modules based on the failure mode information, wherein digitalinformation is segmented into digital information segments and wherein adigital information segment of the digital information segments isencoded using a dispersed storage error coding function to produce a setof encoded data slices, wherein an encoded data slices of the set ofencoded data slices has a slice name with a particular pillar reference.

When the container control module 331 is associated with a DSN, thecontainer control module 331 manages the storage mapping information ofa plurality of sets of encoded data slices, wherein the plurality ofstorage modules are grouped into a set of pillar storage units, whereinencoded data slices of the plurality of sets of encoded data sliceshaving a common pillar reference within their respective slices namesare mapped to one of the set of pillar storage units having the commonpillar reference, wherein digital information is segmented into digitalinformation segments and wherein a digital information segment of thedigital information segments is encoded using a dispersed storage errorcoding function to produce a set of encoded data slices, wherein anencoded data slices of the set of encoded data slices has a slice namewith the common pillar reference.

The container control module 331 is further operable to receive a dataaccess request 346, from a source external to the maintenance-freestorage container 330 via the DSN interface 32, and the processingmodule 332 interprets the data access request 346 based on the storagemapping information 350 to identify one or more of the plurality ofstorage modules to produce one or more identified storage modules. Thedata access request 346 is regarding one or more encoded data slices,wherein digital information is segmented into digital informationsegments and wherein a digital information segment of the digitalinformation segments is encoded using a dispersed storage error codingfunction to produce a set of encoded data slices. The data includes aplurality of encoded data slices, which includes at least one encodeddata slice of the set of encoded data slices. The processing module 332of the container control module 331 is further operable to generate anin-container data access request 360 based on the data access request346 and the one or more identified storage modules. The transceiver 334is operable to transmit the in-container data access request to the oneor more identified storage modules. The processing module 332 is furtheroperable to generate an access response 348 and send the access response348 to the DSN via the DSN interface 32. The access response 348 mayinclude one or more of an encoded data slice (e.g., as a result of aread slice access request 346) and a command.

The container control module 331 is further operable to determine thatthe data access request is regarding writing encoded data slices thathave related slices names (e.g., slice names of contiguous datasegments, slice names associated with a common data segment) andidentify one of the plurality of storage modules for storing the encodeddata slices. Next, the container control module 331 generates relatedlocation information (e.g., consecutive sectors for consecutive slicenames) for the encoded data slices within the identified one of theplurality of storage modules, updates the storage mapping information350 based on the related location information, and generates thein-container data access request 360 based on the related locationinformation.

The transceiver 338 of the storage module functions to receive at leasta portion of the in-container data access request 360 from the containercontrol module 331. For example, transceiver 338 receives containedwireless signals 362 generated by a transceiver 334 when wirelesssignals are utilized. Alternatively, transceiver 338 receives wirelinesignals generated by transceiver 334 one wireline signals are utilized.The control module 340 generates a control signal 364 from the at leasta portion of the in-container data access request 360. The controlsignal 364 includes one or more of a storage medium identifier when theone or more storage mediums 343 includes a plurality of storage mediums343, position information (e.g. head position), and a sector number(e.g., a disc sector number).

The storage medium interface 342 includes a servo unit and a head unit,wherein the servo unit converts the control signal 364 into a head unitcontrol signal and wherein, in accordance with the head unit controlsignal, the head unit is positioned relative to a storage medium of theone or more storage mediums to access the data. The storage mediuminterface 342 functions to access a portion of the data from the one ormore storage mediums 343 based on the control signal 364. For example,the storage medium interface 342 converts data 358 into magnetic and/oroptical signals for transfer to the storage medium 343 when writing dataand detects magnetic and/or optical signals from the storage medium 343to reproduce data 358 when reading data.

In an encoded data slice retrieval example of operation, the processingmodule 332 receives an access request 346 (e.g., a slice retrievalrequest) from the DSN via the DSN interface 32. The processing module332 accesses the slice location memory 336 to retrieve the storagemapping information 350. Next, the processing module 332 identifies anentry of the storage mapping information 350 utilizing a slice name(e.g., 395C) of the access request 346. The processing module 332extracts a storage module ID (e.g., storage module 1_3) of the storagemodule ID field 354 and access request information (e.g., drive 10sector 9) of the access request information field 356 corresponding toslice name (e.g., 395C) of the slice name field 352. Next, theprocessing module 332 generates an in-container access request 360utilizing the access request information. The transceiver 334 convertsthe access request 360 into contained wireless signals 362 and sends thecontained wireless signals 362 to storage module 1 _(—3).

Continuing the preceding example, the transceiver 338 of memory module1_3 receives the contained wireless signals 362 and provides the accessrequest information 360 to the control module 340. The control module340 translates the access request information 360 into control signals364 to operate the storage medium interface 342 to spin the disk acrossthe head such that the head reads bits of a desired slice of therequest. The storage medium interface 342 reads data 358 from thestorage medium 343 of the desired slice and provides the data 358 to thetransceiver 338 of the memory module 1_3. The transceiver 338 convertsthe data 358 into contained wireless signals 362 and transmits thecontained wireless signals 362 to the transceiver 334. The transceiver334 receives the contained wireless signals 362 and decodes thecontained wireless signals 362 to reproduce data 358 (e.g., thatincludes the desired encoded data slice). The processing module 332generates an access response 348 that includes the reproduced encodeddata slice and sends the access response 348 to the DSN via the DSNinterface 32.

In an encoded data slice storage example of operation, the processingmodule 332 receives an access request 346 that includes a write slicerequest from the DSN via the DSN interface 32. The processing module 332retrieves the storage mapping information 350 from the slice locationmemory 336 to identify an available storage module, an available storagemedium 343 (e.g. drive) within the storage module, and an availableposition within the storage medium 343. The processing module 332generates a new slice location information entry that includes one ormore of a slice name of the request, integrity information of the slice(e.g., a hash over the slice), a storage module ID, a drive ID, andaccess request information (e.g., position information). The processingmodule 332 modifies the storage mapping information 350 to include thenew slice location information entry and stores the updated storagemapping information 350 in the slice location memory 336.

Continuing the preceding example, the processing module 332 generates anin-container access request 360 that includes access request informationand data 358 that includes an encoded data slice of the access request346. The processing module 332 sends the data 358 and the access request360 to the selected storage module utilizing the transceiver 334 viacontained wireless signals 362. A transceiver 338 associated with theselected storage module receives the contained wireless signals 362 anddecodes the contained wireless signals 362 to reproduce the encoded dataslice as data 358 and reproduces the access request 360. The controlmodule 340 produces control signals 364 based on the access request 360to operate the storage medium interface 342 (e.g., servos to spin a discassociated with the drive ID) pass the head such that the storage mediuminterface 342 (e.g. a head) writes data 358 (e.g., the encoded dataslice) to the disk to store the encoded data slice.

FIG. 19B is a flowchart illustrating an example of accessing a storagemodule of a maintenance free storage container. The method begins atstep 370 where a processing module (e.g., of a container control module)determines failure mode information for a plurality of storage modulesof a maintenance-free storage container that allows for multiple storagemodules of the plurality of storage modules to be in a failure modewithout replacement. The method continues at step 372 where theprocessing module manages storage mapping information of data contentwithin the plurality of storage modules based on the failure modeinformation. The managing includes managing the storage mappinginformation of encoded data slices having common pillar referenceswithin their respective slices names within the plurality of storagemodules based on the failure mode information, wherein digitalinformation is segmented into digital information segments and wherein adigital information segment of the digital information segments isencoded using a dispersed storage error coding function to produce a setof encoded data slices, wherein an encoded data slices of the set ofencoded data slices has a slice name with a particular pillar reference.

The managing further includes managing the storage mapping informationof a plurality of sets of encoded data slices, wherein the plurality ofstorage modules are grouped into a set of pillar storage units, whereinencoded data slices of the plurality of sets of encoded data sliceshaving a common pillar reference within their respective slices namesare mapped to one of the set of pillar storage units having the commonpillar reference, wherein digital information is segmented into digitalinformation segments and wherein a digital information segment of thedigital information segments is encoded using a dispersed storage errorcoding function to produce a set of encoded data slices, wherein anencoded data slices of the set of encoded data slices has a slice namewith the common pillar reference.

The method continues at step 374 where the processing module receives adata access request. The receiving includes receiving the data accessrequest regarding one or more encoded data slices, wherein digitalinformation is segmented into digital information segments, wherein adigital information segment of the digital information segments isencoded using a dispersed storage error coding function to produce a setof encoded data slices, and wherein the data includes a plurality ofencoded data slices, which includes at least one encoded data slice ofthe set of encoded data slices.

The method continues at step 376 where the processing module interpretsthe data access request based on the storage mapping information toidentify one or more of the plurality of storage modules to produce oneor more identified storage modules (e.g., a lookup by slice name). Themethod continues at step 378 where the processing module generates anin-container data access request based on the data access request andthe one or more identified storage modules. The method continues at step380 where the processing module sends the in-container data accessrequest to the one or more identified storage modules.

When the data access request is regarding writing encoded data slicesthat have related slice names, processing module determines that thedata access request is regarding writing encoded data slices that haverelated slices names and identifies one of the plurality of storagemodules for storing the encoded data slices. Next, the processing modulegenerates related location information (e.g., consecutive sectors forconsecutive slice names) for the encoded data slices within theidentified one of the plurality of storage modules and updates thestorage mapping information based on the related location information.Next, the processing module generates the in-container data accessrequest based on the related location information (e.g., position infofor both slices).

The method continues at step 382 where one of the one or more identifiedstorage modules receives at least a portion of the in-container dataaccess request from the container interface module. The method continuesat step 384 where the one of the one or more identified storage modulesgenerates a control signal from the at least a portion of thein-container data access request. The control signal includes one ormore of a storage medium identifier when the one or more storage mediumsincludes a plurality of storage mediums, position information, and asector number. The method continues at step 386 where the one of the oneor more identified storage modules accesses a portion of data from oneor more storage mediums of the by the one of the one or more identifiedstorage modules, based on the control signal.

As may be used herein, the terms “substantially” and “approximately”provides an industry-accepted tolerance for its corresponding termand/or relativity between items. Such an industry-accepted toleranceranges from less than one percent to fifty percent and corresponds to,but is not limited to, component values, integrated circuit processvariations, temperature variations, rise and fall times, and/or thermalnoise. Such relativity between items ranges from a difference of a fewpercent to magnitude differences. As may also be used herein, theterm(s) “operably coupled to”, “coupled to”, and/or “coupling” includesdirect coupling between items and/or indirect coupling between items viaan intervening item (e.g., an item includes, but is not limited to, acomponent, an element, a circuit, and/or a module) where, for indirectcoupling, the intervening item does not modify the information of asignal but may adjust its current level, voltage level, and/or powerlevel. As may further be used herein, inferred coupling (i.e., where oneelement is coupled to another element by inference) includes direct andindirect coupling between two items in the same manner as “coupled to”.As may even further be used herein, the term “operable to” or “operablycoupled to” indicates that an item includes one or more of powerconnections, input(s), output(s), etc., to perform, when activated, oneor more its corresponding functions and may further include inferredcoupling to one or more other items. As may still further be usedherein, the term “associated with”, includes direct and/or indirectcoupling of separate items and/or one item being embedded within anotheritem. As may be used herein, the term “compares favorably”, indicatesthat a comparison between two or more items, signals, etc., provides adesired relationship. For example, when the desired relationship is thatsignal 1 has a greater magnitude than signal 2, a favorable comparisonmay be achieved when the magnitude of signal 1 is greater than that ofsignal 2 or when the magnitude of signal 2 is less than that of signal1.

As may also be used herein, the terms “processing module”, “processingcircuit”, and/or “processing unit” may be a single processing device ora plurality of processing devices. Such a processing device may be amicroprocessor, micro-controller, digital signal processor,microcomputer, central processing unit, field programmable gate array,programmable logic device, state machine, logic circuitry, analogcircuitry, digital circuitry, and/or any device that manipulates signals(analog and/or digital) based on hard coding of the circuitry and/oroperational instructions. The processing module, module, processingcircuit, and/or processing unit may be, or further include, memoryand/or an integrated memory element, which may be a single memorydevice, a plurality of memory devices, and/or embedded circuitry ofanother processing module, module, processing circuit, and/or processingunit. Such a memory device may be a read-only memory, random accessmemory, volatile memory, non-volatile memory, static memory, dynamicmemory, flash memory, cache memory, and/or any device that storesdigital information. Note that if the processing module, module,processing circuit, and/or processing unit includes more than oneprocessing device, the processing devices may be centrally located(e.g., directly coupled together via a wired and/or wireless busstructure) or may be distributedly located (e.g., cloud computing viaindirect coupling via a local area network and/or a wide area network).Further note that if the processing module, module, processing circuit,and/or processing unit implements one or more of its functions via astate machine, analog circuitry, digital circuitry, and/or logiccircuitry, the memory and/or memory element storing the correspondingoperational instructions may be embedded within, or external to, thecircuitry comprising the state machine, analog circuitry, digitalcircuitry, and/or logic circuitry. Still further note that, the memoryelement may store, and the processing module, module, processingcircuit, and/or processing unit executes, hard coded and/or operationalinstructions corresponding to at least some of the steps and/orfunctions illustrated in one or more of the Figures. Such a memorydevice or memory element can be included in an article of manufacture.

The present invention has been described above with the aid of methodsteps illustrating the performance of specified functions andrelationships thereof. The boundaries and sequence of these functionalbuilding blocks and method steps have been arbitrarily defined hereinfor convenience of description. Alternate boundaries and sequences canbe defined so long as the specified functions and relationships areappropriately performed. Any such alternate boundaries or sequences arethus within the scope and spirit of the claimed invention. Further, theboundaries of these functional building blocks have been arbitrarilydefined for convenience of description. Alternate boundaries could bedefined as long as the certain significant functions are appropriatelyperformed. Similarly, flow diagram blocks may also have been arbitrarilydefined herein to illustrate certain significant functionality. To theextent used, the flow diagram block boundaries and sequence could havebeen defined otherwise and still perform the certain significantfunctionality. Such alternate definitions of both functional buildingblocks and flow diagram blocks and sequences are thus within the scopeand spirit of the claimed invention. One of average skill in the artwill also recognize that the functional building blocks, and otherillustrative blocks, modules and components herein, can be implementedas illustrated or by discrete components, application specificintegrated circuits, processors executing appropriate software and thelike or any combination thereof.

The present invention may have also been described, at least in part, interms of one or more embodiments. An embodiment of the present inventionis used herein to illustrate the present invention, an aspect thereof, afeature thereof, a concept thereof, and/or an example thereof. Aphysical embodiment of an apparatus, an article of manufacture, amachine, and/or of a process that embodies the present invention mayinclude one or more of the aspects, features, concepts, examples, etc.described with reference to one or more of the embodiments discussedherein. Further, from figure to figure, the embodiments may incorporatethe same or similarly named functions, steps, modules, etc. that may usethe same or different reference numbers and, as such, the functions,steps, modules, etc. may be the same or similar functions, steps,modules, etc. or different ones.

While the transistors in the above described figure(s) is/are shown asfield effect transistors (FETs), as one of ordinary skill in the artwill appreciate, the transistors may be implemented using any type oftransistor structure including, but not limited to, bipolar, metal oxidesemiconductor field effect transistors (MOSFET), N-well transistors,P-well transistors, enhancement mode, depletion mode, and zero voltagethreshold (VT) transistors.

Unless specifically stated to the contra, signals to, from, and/orbetween elements in a figure of any of the figures presented herein maybe analog or digital, continuous time or discrete time, and single-endedor differential. For instance, if a signal path is shown as asingle-ended path, it also represents a differential signal path.Similarly, if a signal path is shown as a differential path, it alsorepresents a single-ended signal path. While one or more particulararchitectures are described herein, other architectures can likewise beimplemented that use one or more data buses not expressly shown, directconnectivity between elements, and/or indirect coupling between otherelements as recognized by one of average skill in the art.

The term “module” is used in the description of the various embodimentsof the present invention. A module includes a processing module, afunctional block, hardware, and/or software stored on memory forperforming one or more functions as may be described herein. Note that,if the module is implemented via hardware, the hardware may operateindependently and/or in conjunction software and/or firmware. As usedherein, a module may contain one or more sub-modules, each of which maybe one or more modules.

While particular combinations of various functions and features of thepresent invention have been expressly described herein, othercombinations of these features and functions are likewise possible. Thepresent invention is not limited by the particular examples disclosedherein and expressly incorporates these other combinations.

What is claimed is:
 1. A method for rebuilding an encoded data slice fora maintenance free storage container, the method comprises: detecting astorage error of the encoded data slice associated with a storage serverof a plurality of storage servers within the maintenance free storagecontainer, wherein the maintenance free storage container allows formultiple storage servers of the plurality of storage servers to be in afailure mode without replacement, wherein data is encoded using adispersed storage error coding function to produce a set of encoded dataslices, which includes the encoded data slice, and wherein at least someencoded data slices of the set of encoded data slices are stored inother storage servers of the plurality of storage servers; determiningfailure mode information for the storage server and the other storageservers; determining a rebuilding protocol for the encoded data slicebased on the failure mode information and whether at least a decodethreshold of the other storage servers are available; when thedetermined rebuilding protocol is a zero information gain (ZIG)protocol: identifying a decode threshold number of storage servers fromthe other storage servers of the maintenance free storage container andfrom storage servers of another maintenance free storage container;retrieving zero information gain (ZIG) partial encoded data slices fromthe decode threshold number of storage servers; and decoding the ZIGpartial encoded data slices utilizing a ZIG dispersed storage errorcoding function to reproduce the encoded data slice.
 2. The method ofclaim 1, wherein the determining the rebuilding protocol comprises:determining whether quantity of the other storage servers is at leastequal to a decode threshold number; and when the quantity of the otherstorage servers is less than the decode threshold number, identifyingthe ZIG protocol.
 3. The method of claim 1 further comprises: when thedetermined rebuilding protocol is a data-based rebuild protocol:retrieving a decode threshold number of encoded data slices of the setof encoded data slices from the other storage servers; decoding thedecode threshold number of encoded data slices utilizing the dispersedstorage error coding function to reproduce the data; and encoding thedata utilizing the dispersed storage error coding function to reproducethe encoded data slice.
 4. The method of claim 1, wherein the detectingthe storage error of the encoded data slice comprises at least one of:indicating the storage error when a list response from the storageserver compares unfavorably to at least another list response from theother storage servers; indicating the storage error when a calculatedslice integrity value compares unfavorably to a retrieved sliceintegrity value corresponding to the encoded data slice; indicating thestorage error when determining that the storage server is in the failuremode; receiving a storage error message; and receiving a rebuildingrequest, wherein the rebuilding request includes a slice name associatedwith the encoded data slice.
 5. The method of claim 1, wherein thedetermining the failure mode information comprises at least one of:determining that one or more storage locations within a first storageserver of the storage server and of the other storage servers hasfailed; determining that a second storage server of the storage serverand of the other storage servers has failed; and determining that athird storage server of the storage server and of the other storageservers is operating at less than a desired storage level but greaterthan a storage failure level.
 6. The method of claim 1, wherein theretrieving the decode threshold number of zero information gain (ZIG)partial encoded data slices corresponding to the encoded data slicecomprises: generating a decode threshold number of ZIG partial encodeddata slice requests based on identity of the encoded data slice andpillar numbers associated with the decode threshold number of storageservers; outputting the decode threshold number of ZIG partial encodeddata slice requests to the decode threshold number of storage servers;and receiving the decode threshold number of ZIG partial encoded dataslices from the decode threshold number of storage servers.
 7. Themethod of claim 1, wherein the decoding the decode threshold number ofZIG partial encoded data slices further comprises: exclusive ORing thedecode threshold number of ZIG partial encoded data slices to reproducethe encoded data slice.
 8. A dispersed storage (DS) module comprises: afirst module, when operable within a computing device, causes thecomputing device to: detect a storage error of an encoded data sliceassociated with a storage server of a plurality of storage serverswithin a maintenance free storage container, wherein the maintenancefree storage container allows for multiple storage servers of theplurality of storage servers to be in a failure mode withoutreplacement, wherein data is encoded using a dispersed storage errorcoding function to produce a set of encoded data slices, which includesthe encoded data slice, and wherein at least some encoded data slices ofthe set of encoded data slices are stored in other storage servers ofthe plurality of storage servers; a second module, when operable withinthe computing device, causes the computing device to: determine failuremode information for the storage server and the other storage servers; athird module, when operable within the computing device, causes thecomputing device to: determine a rebuilding protocol for the encodeddata slice based on the failure mode information and whether at least adecode threshold of the other storage servers are available; and afourth module, when operable within the computing device, causes thecomputing device to: when the determined rebuilding protocol is a zeroinformation gain (ZIG) protocol: identify a decode threshold number ofstorage servers from the other storage servers of the maintenance freestorage container and from storage servers of another maintenance freestorage container; retrieve zero information gain (ZIG) partial encodeddata slices from the decode threshold number of storage servers; anddecode the ZIG partial encoded data slices utilizing a ZIG dispersedstorage error coding function to reproduce the encoded data slice. 9.The DS module of claim 8, wherein the third module functions todetermine the rebuilding protocol by: determining whether quantity ofthe other storage servers is at least equal to a decode thresholdnumber; and when the quantity of the other storage servers is less thanthe decode threshold number, identifying the ZIG protocol.
 10. The DSmodule of claim 8, wherein the fourth module is further operable to:when the determined rebuilding protocol is a data-based rebuildprotocol: retrieve a decode threshold number of encoded data slices ofthe set of encoded data slices from the other storage servers; decodethe decode threshold number of encoded data slices utilizing thedispersed storage error coding function to reproduce the data; andencode the data utilizing the dispersed storage error coding function toreproduce the encoded data slice.
 11. The DS module of claim 8, whereinthe first module functions to detect the storage error of the encodeddata slice by at least one of: indicating the storage error when a listresponse from the storage server compares unfavorably to at leastanother list response from the other storage servers; indicating thestorage error when a calculated slice integrity value comparesunfavorably to a retrieved slice integrity value corresponding to theencoded data slice; indicating the storage error when determining thatthe storage server is in the failure mode; receiving a storage errormessage; and receiving a rebuilding request, wherein the rebuildingrequest includes a slice name associated with the encoded data slice.12. The DS module of claim 8, wherein the second module functions todetermine the failure mode information by at least one of: determiningthat one or more storage locations within a first storage server of thestorage server and of the other storage servers has failed; determiningthat a second storage server of the storage server and of the otherstorage servers has failed; and determining that a third storage serverof the storage server and of the other storage servers is operating atless than a desired storage level but greater than a storage failurelevel.
 13. The DS module of claim 8, wherein the fourth module functionsto retrieve the decode threshold number of zero information gain (ZIG)partial encoded data slices corresponding to the encoded data slice by:generating a decode threshold number of ZIG partial encoded data slicerequests based on identity of the encoded data slice and pillar numbersassociated with the decode threshold number of storage servers;outputting the decode threshold number of ZIG partial encoded data slicerequests to the decode threshold number of storage servers; andreceiving the decode threshold number of ZIG partial encoded data slicesfrom the decode threshold number of storage servers.
 14. The DS moduleof claim 8, wherein the fourth module further functions to decode thedecode threshold number of ZIG partial encoded data slices by: exclusiveORing the decode threshold number of ZIG partial encoded data slices toreproduce the encoded data slice.